Direct Liquid Propane Injection? 1

[pricej20]

I am currently searching for an alternative fuel to convert my truck. I have settled on Propane. But in my research i found that the closer the injector is to the combustion chamber the more power and efficiency are acheived.

I was curious if anyone has come across a Direct Injection Propane System, in liquid form. I can only find systems that use vapor and another that uses liquid but is in the intake.

Any info is appreciated,

Thanks,

pricej20

 

[turbocohen]

oops, meant to link this one..

http://www.google.com/patents?id=CI0DAAAAEBAJ&dq=siemens+cohen

 

[turbocohen]

and another..

http://www.google.com/patents?id=zdEJAAAAEBAJ&dq=siemens+cohen

 

[roundman]

The Schwans company owns a proprietary liquid propane injection system that is used on all their delivery trucks.
They were going to market the system, and even had a website, but it was never finished and has now disappeared. I guess they thought the better of it.
An automotive engineer named David Bennett patented the system in 1998 and Schwans bought him out, patent, manufacturing operation and all. You can look at his drawings at Patents on line.
Since LPG has a slightly lower HHV than gasoline and with a gaseous propane carbureted system so much of the air available for combustion is displaced by the fuel, carbureted propane systems were considerably less efficient than gasoline systems. Turbocharging was about the only way to get the lost efficiency back.
The liquid injection system has nozzles that expel the propane right above the intake valve. At speed, a considerable amount of liquid propane makes it into the combustion chamber. The phase change occuring within the combustion chamber cools the air/fuel charge and contributes to the overall compression ratio. This system is supposed to be more efficient than gasoline.

 

[Lou Scannon]

"Efficiency" is probably not the term you meant to use. I believe you are trying to describe the power loss caused by displacement of air by a gaseous fuel.
Efficiency of an Otto cycle engine is less a function of the fuel itself than many other parameters, which can and should be optimized for a particular fuel.